We present a method of single-frame reconstruction in off-axis digital holography with Kronecker-product interpolation to maximize spatial-frequency extraction. The Kronecker-product interpolation operated on a one-frame off-axis digital hologram can generate several aliasing spectra in its Fourier domain, where the zero-order aliasing spectra in the extrapolation region can be suppressed effectively. After adding all aliasing spectrum regions and substituting each aliasing spectrum in place with their sum, spectrum interception with a larger scope for filtering can be made in one of the aliasing spectrum regions. The experimental results demonstrate that the method is valid to improve the resolution in off-axis digital holography.